Method of heat treating steel



Patented Oct. 1, 1940 METHOD OF HEAT TREATDIG STEEL Sidney S. Frost,Eastport, Maine, assignor of forty one -hundredths to Maxwell K.

Detroit, Mich.

Murphy,

No Drawing. Application January it, 1939, Serial No. 243:9.706

(UL lid-Alt) 2 Claims.

This invention relates to methods of heat treating steel.

It pertains specifically to methods of quenching steel whereby poorgrades of carbon steel may be converted into steel that is equivalent tothe 5 finest tool steel.

It is a matter ofcommon knowledge that the softer grades of iron may beconverted into steel of various degrees of hardness by theaddition ofmolybdenum, nickel, tungsten, etc., under the proper conditions oftemperature. Such processes however, are expensive to carry out and areemployed only when it is desired to manufacture steel for use as cuttingtools, etc.

I have found that low grades of carbon steel may be converted into steelthat is the full equivalent of the more expensive grades of steel forcertain purposes by a simple process that may be performed by anyonewithout the use of complicated apparatus.

It is, accordingly, the principal object of my invention to provide amethod of treating the soft and inexpensive grades of steel whereby theyare converted into a harder grade that is, for some purposes, equivalentto the finest tool steel without necessitating the addition of otheringredients to the steel.

Another object of 'my invention is to provide a method of increasing thehardness of steel that is simple and inexpensive to carry out.

Other objects of my invention will be apparent as the descriptionproceeds.

As a first step in the carrying out of my process, I prepare a quenchingbath of the following ingredients: refined petroleum, animal fat, sodiumchloride, sodium phosphate, sodium bicarbonate and acid. The proportionsof the ingredients may be varied somewhat, but I have found that aquenching bath made up as follows gives very good results.

Kerosene oil gallons 5 Beer tallow do 1 Common table salt pounds 2/Sodium phosphate "drams..- 10

5 Sodium bicarbonate do.. 10

4 Tartaric acid do 5 If desired, two ounces of oil of coriander may beadded to the bath as a deodorant.

The bath is made up by melting th tallow and 50 adding the salt thereto.This mixture is then quires frequent sharpening.

poured into the kerosene, in which the sodium phosphate and sodiumbicarbonate have previously been dissolved. The mixture is thenthoroughly stirred and, it thought desirable, the oil of coriander maythen be added.

The steel to be treated is heated uniformly to approximately 1500 F. andis plunged into the bath in as quick a manner as possible and left thereuntil cool.

The above described process has been found to be particularly effectivein hardening such tools W as chisels, axes and planer blades which arein common household and farm use, and which are usually made of thecheaper grades of carbon steel which loses its edge very quickly and remThe ordinary hardware store variety of axes, planes, chisels, etc., whentreated as outlined above, will retain their edges for long periods oftime without resharpening, and will not become notched or pitted evenwhen used to cut nails and wire. Because of the simplicity of myprocess, and because the ingredients required for my quenching bath areinexpensive and may be purchased everywhere, my process is capable ofbeing carried out by the average blacksmith.

It is to be understood that-I have described only one specificembodiment of my invention, which is to be taken as illustrative and notas limiting, except as defined in the following claims.

I claim:

1. The method of heat treating metals which comprises heating the metalto be treated to approximately l500 F. and quickly plunging it into abath composed of the following ingredients: 5 gallons kerosene oil, lgallon beef tallow. /2 pound common table salt, 10 drams sodiumphosphate, 10 drams sodium bicarbonate and 5 drams tartaric acid.

2. The method of heat treating steel which comprises heating the metalto be treated to approximately 1500 F. and quenching it in a bathconsisting of kerosene oil and beef tallow mixed 4 together in quantityratio of substantially 5 to 1 together with a relatively small quantityof common table salt, sodium phosphate, sodium bicarbonate and tartaricacid.

SIDNEY S. FROST.

